[CRIU] failing to dump tmpfs?

Wed Jan 13 05:12:19 PST 2016

On 01/09/2016 07:07 AM, Tycho Andersen wrote:
> 
> Hi all,
> 
> I have a strange problem :). I'm getting,
> 
> (00.280617) Dumping task cwd id 0x2b root id 0x2b
> (00.280697) mnt: Dumping mountpoints
> (00.280702) mnt:        132: 34:/ @ ./run/lock
> (00.280714) mnt: Path `/run/lock' resolved to `./run/lock' mountpoint
> tar: /proc/self/fd/0: Cannot open: Not a directory

Tar refuses to open what we've passed to it as a mountpoint dir :(
Can you put some more logging into tmpfs dump to see what exactly
is passed to tar?

> tar: Error is not recoverable: exiting now
> (00.283581) Error (util.c:666): exited, status=2
> (00.283598) Error (mount.c:1220): mnt: Can't dump tmpfs content
> 
> With a container that has the following mountinfo:
> 
> 127 128 253:1 /var/lib/lxd2/containers/unpriv/rootfs / rw,relatime master:1 - ext4 /dev/vda1 rw,data=ordered
> 194 127 0:40 / /dev rw,nodev,relatime - tmpfs none rw,size=100k,mode=755,uid=100000,gid=100000
> 195 127 0:45 / /proc rw,nosuid,nodev,noexec,relatime - proc proc rw
> 196 197 0:45 /sys/net /proc/sys/net rw,nosuid,nodev,noexec,relatime - proc proc rw
> 197 195 0:45 /sys /proc/sys ro,nosuid,nodev,noexec,relatime - proc proc rw
> 198 195 0:45 /sysrq-trigger /proc/sysrq-trigger ro,nosuid,nodev,noexec,relatime - proc proc rw
> 199 127 0:46 / /sys rw,nosuid,nodev,noexec,relatime - sysfs sysfs rw
> 200 199 0:46 / /sys ro,nosuid,nodev,noexec,relatime - sysfs sysfs rw
> 201 200 0:46 / /sys/devices/virtual/net rw,nodev,relatime - sysfs sysfs rw
> 202 201 0:46 /devices/virtual/net /sys/devices/virtual/net rw,nosuid,nodev,noexec,relatime - sysfs sysfs rw
> 203 200 0:37 / /sys/fs/fuse/connections rw,relatime master:27 - fusectl fusectl rw
> 204 200 0:7 / /sys/kernel/debug rw,relatime master:25 - debugfs debugfs rw
> 205 200 0:12 / /sys/kernel/security rw,nosuid,nodev,noexec,relatime master:8 - securityfs securityfs rw
> 206 200 0:24 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime master:11 - pstore pstore rw
> 207 194 0:44 / /dev/mqueue rw,nodev,relatime - mqueue mqueue rw
> 208 194 0:6 /console /dev/console rw,nosuid,relatime master:2 - devtmpfs udev rw,size=981956k,nr_inodes=245489,mode=755
> 209 194 0:6 /full /dev/full rw,nosuid,relatime master:2 - devtmpfs udev rw,size=981956k,nr_inodes=245489,mode=755
> 210 194 0:6 /null /dev/null rw,nosuid,relatime master:2 - devtmpfs udev rw,size=981956k,nr_inodes=245489,mode=755
> 211 194 0:6 /random /dev/random rw,nosuid,relatime master:2 - devtmpfs udev rw,size=981956k,nr_inodes=245489,mode=755
> 212 194 0:6 /tty /dev/tty rw,nosuid,relatime master:2 - devtmpfs udev rw,size=981956k,nr_inodes=245489,mode=755
> 213 194 0:6 /urandom /dev/urandom rw,nosuid,relatime master:2 - devtmpfs udev rw,size=981956k,nr_inodes=245489,mode=755
> 215 194 0:6 /zero /dev/zero rw,nosuid,relatime master:2 - devtmpfs udev rw,size=981956k,nr_inodes=245489,mode=755
> 217 197 0:48 / /proc/sys/fs/binfmt_misc rw,relatime master:104 - binfmt_misc binfmt_misc rw
> 218 194 253:1 /var/lib/lxd2/devlxd /dev/lxd rw,relatime master:1 - ext4 /dev/vda1 rw,data=ordered
> 219 194 253:1 /var/lib/lxd2/shmounts/unpriv /dev/.lxd-mounts rw,relatime master:1 - ext4 /dev/vda1 rw,data=ordered
> 220 200 0:47 / /sys/fs/cgroup rw,nodev,relatime - tmpfs cgroup rw,size=12k,mode=755,uid=100000,gid=100000
> 221 220 0:22 /cgmanager /sys/fs/cgroup/cgmanager rw master:9 - tmpfs tmpfs rw,mode=755
> 222 195 0:54 /proc/cpuinfo /proc/cpuinfo rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 223 195 0:54 /proc/diskstats /proc/diskstats rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 224 195 0:54 /proc/meminfo /proc/meminfo rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 225 195 0:54 /proc/stat /proc/stat rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 226 195 0:54 /proc/uptime /proc/uptime rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 227 220 0:54 /cgroup/blkio /sys/fs/cgroup/blkio rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 228 220 0:54 /cgroup/cpu,cpuacct /sys/fs/cgroup/cpu,cpuacct rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 229 220 0:54 /cgroup/cpuset /sys/fs/cgroup/cpuset rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 230 220 0:54 /cgroup/devices /sys/fs/cgroup/devices rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 231 220 0:54 /cgroup/freezer /sys/fs/cgroup/freezer rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 232 220 0:54 /cgroup/hugetlb /sys/fs/cgroup/hugetlb rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 233 220 0:54 /cgroup/memory /sys/fs/cgroup/memory rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 234 220 0:54 /cgroup/name=systemd /sys/fs/cgroup/systemd rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 235 220 0:54 /cgroup/net_cls,net_prio /sys/fs/cgroup/net_cls,net_prio rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 236 220 0:54 /cgroup/perf_event /sys/fs/cgroup/perf_event rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 237 220 0:54 /cgroup/pids /sys/fs/cgroup/pids rw,nosuid,nodev,relatime master:96 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
> 129 194 0:49 / /dev/pts rw,relatime - devpts devpts rw,gid=100005,mode=620,ptmxmode=666
> 130 194 0:50 / /dev/shm rw,nosuid,nodev - tmpfs tmpfs rw,uid=100000,gid=100000
> 131 127 0:51 / /run rw,nosuid,nodev - tmpfs tmpfs rw,mode=755,uid=100000,gid=100000
> 132 131 0:52 / /run/lock rw,nosuid,nodev,noexec,relatime - tmpfs tmpfs rw,size=5120k,uid=100000,gid=100000
> 
> Nothing seems overmounted (or otherwise obviously wrong), from inside the
> container I have:
> 
> drwxrwxrwt  4 root root   80 Jan  9 03:56 lock
> 
> Any ideas?
> 
> Thanks,
> 
> Tycho
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